Face-milling method and apparatus

An indexable face-milling metal-cutting insert comprising two substantially parallel side faces interconnected by an edge surface structure to define at least four and not more than six cutting corners;

• an intersection of said edge surface structure and each of said side faces at each of said cutting corners forming a pair of minor cutting edges intersecting one another substantially at a bisector of said cutting corner to form an obtuse angle therebetween;
• an intersection of said edge surface structure and each of said side faces at locations between adjacent ones of said cutting corners forming major cutting edges;
• each major cutting edge intersecting an associated one of said minor cutting edges, whereby each major cutting edge and its associated minor cutting edge together define a cooperating pair of cutting edges;
• there being at least eight of said cooperating pairs on each of said side faces;
• said insert being indexable to bring only one of said cooperating pairs at a time into cutting relationship with a workpiece, with said side face being operable as a chip surface and said edge surface structure operable as a clearance surface;
• each side face including two of said cooperating pairs at each of said cutting corners, said two pairs disposed on opposite sides of said corner bisector;
• said minor cutting edges being sharper than said major cutting edges, each of said side faces including concave chip-forming surfaces disposed inwardly of said major and minor cutting edges.